Radiolabeled compounds have long been used in diagnostic and therapeutic procedures. Some radio metals have superior properties for use in these procedures. Technetium-99m (Tc-99m) is an ideal radionuclide for scintigraphic imaging because of its radioactive decay properties. It has a single photon energy of 140 keV, a half life of about 6 hours, and it is readily available from a .sup.99 Mo.sup.99m Tc generator.
There is a large family of polyhydric complexes of technetium, with and without carboxylic acid groups, which differ widely in stability. Hwang, et al., Intl. J. of Appl. Radiat. Isot., 36 (6): 475-480 (1975). Hydroxycarboxylates tend to form soluble complexes with transition metals. Technetium (Tc) complexes of these compounds have been used for the nuclear imaging of kidneys, brain, myocardial infarcts and tumors. Russell and Speiser, J. Nucl. Med., 21: 1086-1090 (1980). .sup.99m Tc-D-glucoheptonate is the most widely used imaging agent. It has been used for brain and kidney imaging. Waxman, et al. J.Nucl. Med., 17: 345-348 (1976) and Arnold, et al , J. Nucl. Med.,16: 357-367 (1975). See also, Adler, et al., U.S. Pat. No. 4,027,005. However, .sup.99m Tc-D-glucoheptonate has been less successful as an imaging agent for myocardial infarct. Rossman, et al., J. Nucl. Med.,16: 980-985 (1975).
Much effort has been directed toward evaluating the usefulness of various radionuclides and radiopharmaceuticals for imaging tumor tissue, particularly malignant diseases such as breast carcinoma and colon carcinoma. .sup.18 F-2-fluoro-2-deoxy-D-glucose has been used to image cerebral gliomas, hepatoma, thyroid tumor, liver metastases from colon carcinoma and bone tumors. DiChiro et al., Neurology, 32:1323 (1982); Paul et al., Lancet, 1:50(1985); Joensuu et al., Eur. J. Nucl. Med., 13:502 (1988); Yonekura et al., Eur. J. Nucl. Med., 23:1133 (1982); Ahonen et al., In: Nuclear Med., Proc. ENMC, Stuttgart, N.Y., 441-443 (1986). However, this compound is not appropriate for all types of tumors. Accurate and early detection of tumors is often critical for the successful treatment of these diseases. Tumor imaging agents offer an effective, non-invasive method for early detection and imaging of tumors.